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Newbie type 2001 GTP TUNE change advice wanted/needed

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PeezDaddy

New member
The weather's getting much cooler and my son wants to drag race his car one more time before the season ends...

I have HPTuners, have had it for years, but have never "tuned" a 2001 supercharged GTP. It only has a cold air kit on it at the moment.

Just as far as ENGINE PERFORMANCE goes....

Is there any MILD tune changes that can be made for the day, or even for the near future that won't immediately blow his engine up? LOL :th_wtf:

What I mean is, are these cars pretty conservative from the factory, as far as timing and fueling are concerned?

Are they factory tuned RICH for longevity?

Could I add a few degrees of timing, and a splash of 100 octane unleaded without worry??
 


Only thing you could really do that I would recommend, is pump the gas out of the tank, fill it up with race gas, and just add timing until you see knock or get to about 20* advance at wot. You probably won't see many gains beyond that. If I were you, I'd find someone with a pulley puller and do a pulley swap with race gas. You'll pros see bigger gains from that than anything.
 
GTPpower said:
Only thing you could really do that I would recommend, is pump the gas out of the tank, fill it up with race gas, and just add timing until you see knock or get to about 20* advance at wot. You probably won't see many gains beyond that. If I were you, I'd find someone with a pulley puller and do a pulley swap with race gas. You'll pros see bigger gains from that than anything.
Click to expand...

Thanks for the reply. That's kinda the info I was fishing for...as in what is a "safe" (generally speaking) total timing number.

Now that you mention it, I think he said he was getting some sort of pulley setup that once you change it once, you can simply unbolt the actual pulleys for any future pulley swaps? I assume he means a 2 piece pulley conversion, which would have made way too much sense to swap on when I had the snout off replacing the coupler a few weeks ago...:th_shakinghead2:

He regularly drives around on fumes, so starting with an empty tank won't be an issue...LOL. :th_laugh-lol2:

Again, generally speaking, do these cars automatically scale the fuel curve, to a point? I'm hoping he gets a WB setup on there because I definitely don't want to trust the NB O2 sensors on a boosted car. My truck was right on the money, but a supercharged setup is not something I want to just start randomly changing things on.

Any other tips or advice is greatly appreciated. The plan is to head to the dragstrip on November 15th. I go to this end of the year event every year and got him a spot this time around.

He won't be whooping his Dad just yet, but I'm sure he'll have some fun.

Me:
http://youtu.be/vvO1BnEbrkE

Him, before we fixed the coupler and MAF meter:
http://youtu.be/lC8pW8WVQhM
 
They don't really scale anything.

With race gas it might run a few tenths quicker because it won't be knocking as much or if at all. But it will still call for the same amount of fuel, which is on the tad rich side of around 11ish afr.
 
Fivefingerdeathpunch said:
They don't really scale anything.

With race gas it might run a few tenths quicker because it won't be knocking as much or if at all. But it will still call for the same amount of fuel, which is on the tad rich side of around 11ish afr.
Click to expand...

I should of clarified...I mean with a smaller pulley adding a little more boost, will the pcm parameters (as is) add fuel to the higher boost?
 


Yeah, your fueling should still be fine. The fuel regulator is boost referenced, and the maf will make any other corrections. Even if it were to run a tad lean, it won't hurt anything on a pretty much stock motor. Main thing is to keep it from knocking.

I love the chevelle. What are you running for drivetrain?
 
Awesome info guys. thanks!

Chevelle is a 439" big block I built about a year ago. Brodix heads, Hydraulic roller camshaft, etc...hooked to a Turbo 400 w/4000 stall and a 12 bolt 4.10 geared rear and drag radials. I just did some more suspension upgrades so I'm hoping for 11.40's on the 15th. Still has functional factory air conditioning too. ;)

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Fivefingerdeathpunch said:
They don't really scale anything.

With race gas it might run a few tenths quicker because it won't be knocking as much or if at all. But it will still call for the same amount of fuel, which is on the tad rich side of around 11ish afr.
Click to expand...

They don't start running that rich at all. Stock files vary from 12.4-12.2 when they enter PE mode and gradually lower a max of -3 by the end of 24 seconds in PE mode....given it's a stock car, the most it'll probably lower on the AFR will be around 2.
They don't run rich at all really if you think about it.
 
They don't run rich at all really if you think about it.
Click to expand...

You sure about that?

If you have HP Tuner go read the ADD vs RPM table, look at the numbers.

At 0 seconds into PE and at 4200 RPM, it will take away -1.2 from the base AFR, that is already 11-11.2 afr, give it 6-8 more seconds and raise the RPM by 1200-1400 to nearly 5500 rpm and it will take away -1.5 from the base AFR, you are now below 11 commanded AFR. 10.7 to 10.9 atleast.

Thats sounds pretty rich to me, it can go even richer and be sub 10's if you lay into it for lng enough.

No matter what you really do and because when these cars shift and don't drop huge amount of rpm during the shift you are always going to running near 11 afr if not slighly lower.
 


I'm positive.
You're right on one point, 97-2000 did use that type of PE vs RPM table, but in the 2001 and later cars (in this case) they leaned out the table. Take a look at a stock file and you will see. At 0 seconds 4200, it's only subtracted roughly .5 from the AFR, it only maxes out at the redline at -1.3 and subsequently drops to between .5 and .75 at the shift where it stays pretty level until 7-8 seconds in. It never really drops the AFR to a consistent 1.0 until after 8 seconds until it begins to add fuel until either A. the end of the run or B at 25 seconds which it drops the AFR to the 9's.
You have to pay close attention to what years you're referring to, because not every PCM is programmed the same, especially when you get into the 2003 and later models.
 
Agreed. I wasn't trying to argue with you, you were right....but these are the things that people tend to overlook when looking for advice.

This here, is one of the reasons why some people tend to zero out the entire time table though 20 seconds.
Nobody in their right mind would stand in these cars for that long to begin with, if they want to keep their 4th gear.
But who am I to give advice? Stock tunes are good for 11 seconds in some cars. :P
 
GTPpower said:
Very nice. What compression and fuel are you running?
Click to expand...

Thanks. It is 10.78:1 and runs fine on 93 octane unleaded. Once in a while, I give it a splash of Cam2 110 (1-2 gallons to a tank) just for the smell. ;)


Reptile said:
They don't start running that rich at all. Stock files vary from 12.4-12.2 when they enter PE mode and gradually lower a max of -3 by the end of 24 seconds in PE mode....given it's a stock car, the most it'll probably lower on the AFR will be around 2.
They don't run rich at all really if you think about it.
Click to expand...

Reptile said:
I'm positive.
You're right on one point, 97-2000 did use that type of PE vs RPM table, but in the 2001 and later cars (in this case) they leaned out the table. Take a look at a stock file and you will see. At 0 seconds 4200, it's only subtracted roughly .5 from the AFR, it only maxes out at the redline at -1.3 and subsequently drops to between .5 and .75 at the shift where it stays pretty level until 7-8 seconds in. It never really drops the AFR to a consistent 1.0 until after 8 seconds until it begins to add fuel until either A. the end of the run or B at 25 seconds which it drops the AFR to the 9's.
You have to pay close attention to what years you're referring to, because not every PCM is programmed the same, especially when you get into the 2003 and later models.
Click to expand...

Thanks for the replies. I just got to work and honestly didn't thoroughly read all the replies, but wondering....to get around it, Can I simply steal some PE settings from a stock file on a 97-2000?

Reptile said:
Agreed. I wasn't trying to argue with you, you were right....but these are the things that people tend to overlook when looking for advice.

This here, is one of the reasons why some people tend to zero out the entire time table though 20 seconds.
Nobody in their right mind would stand in these cars for that long to begin with, if they want to keep their 4th gear.
But who am I to give advice? Stock tunes are good for 11 seconds in some cars. :P
Click to expand...

Are you saying I SHOULD zero out the time table through 20 seconds?

I appreciate anything you guys can offer. Like I said, I just haven't used my HPTuners for any supercharged cars since I got it several years and 2 upgrades ago. When I got it, it was for my old 2000 Camaro SS and was the "serial port" version. :th_scratchhead: Now, it is the MPVI Pro version, and I only really use the software for my personal truck, and here at work to get some of these turds through emissions. ;)

In a nutshell, I haven't stayed very "current" with the software use since I haven't really had a reason to...hence the newbie-ish type questions.

Thanks..
 


Yeah it does. If I were you, I'd still pump the tank out. Last time I did it, my DIC said I only had 4 miles left on that tank, but I still pumped out 2 gallons of old gas.
 
You shouldn't have to worry about pumping the tank. It's a giant pain in the ass for just going to the track.
Put a few gallons in, and run it. If it doesn't have any KR, put a different pulley on and have a blast.
 
I think it's pretty easy, and well worth it. Only takes about an hour at the absolute most. I don't agree with diluting expensive race fuel.
 
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